Should yeasts in respiratory secretions be identified?

Area of Science:

• Medical Microbiology
• Pulmonary Medicine
• Clinical Diagnostics

Background:

• Respiratory secretions are routinely cultured to diagnose pulmonary infections.
• Oropharyngeal contamination of sputum samples is a common issue in diagnostics.
• Understanding the microbial flora of the respiratory tract is crucial for accurate diagnosis.

Purpose of the Study:

• To evaluate the reliability of microscopic oropharyngeal contamination as an indicator for yeast presence in respiratory samples.
• To determine the clinical significance of yeast detection in sputum and bronchial washings.

Main Methods:

• Microscopic examination of 440 sputum and bronchial washing samples for oropharyngeal secretions.
• Culture analysis of the same specimens to identify yeast species.
• Correlation of microscopic contamination with culture results.

Main Results:

• 88% of sputum samples showed oropharyngeal contamination, compared to 21% of bronchial washings.
• Yeasts were recovered from 74% of sputum and 25% of bronchial washings.
• Microscopic contamination was a reliable predictor of yeast presence in respiratory secretions.

Conclusions:

• Microscopic assessment of oropharyngeal contamination is a valuable tool for predicting yeast in respiratory samples.
• Most yeasts found in respiratory secretions are likely normal flora, not indicative of infection.
• Routine identification of common yeasts is not recommended, with the exception of Cryptococcus neoformans.